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AK4141 Datasheet, PDF (27/96 Pages) Asahi Kasei Microsystems – NICAM/A2/EIA-J Digital Stereo Decoder | |||
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[AK4141]
2. ALCãªã«ããªåä½
ALCãªã«ããªåä½ã¯ãWTM2-0ã§è¨å®ãããæé(Table 14)å¾
æ©ãè¡ãããã®éãåºåä¿¡å·ãALCãªã«ããªå¾
æ©ã«ã¦ã³ã¿ãªã»ããã¬ãã«(Table 11)ãè¶ããã¨ããªããã°ALCãªã«ããªåä½ãè¡ãã¾ãããã®ALCãªã«ããª
åä½ã¯è¨å®ãããåºæºã¬ãã«(Table 16)ã¾ã§ZTM1-0ã§è¨å®ããæé(Table 13)ã§ã¼ãã¯ãã¹æ¤åºåä½ãè¡ããª
ãããRGAIN1-0 bitã§è¨å®ããå¤(Table 15)ã ãVOLå¤(L/Rå
±é)ãèªåçã«å¢å ããã¾ãããã®ALCãªã«ããª
åä½ã¯WTM2-0ã§è¨å®ããå¨æã§è¡ãããã¹ã¿ã ããWTM2-0ã§ã®è¨å®ããZTM1-0ã§ã®è¨å®ãé·ãå ´åã«ã
ãã¦ãä¿¡å·ãã¼ãã¯ãã¹ããªãã¨ãã«ã¯ãZTM1-0ã®è¨å®ã§ALCãªã«ããªåä½ãè¡ããã¾ãã
ä¾ãã°ãç¾å¨ã®VOLå¤ã30Hã®å ´åãRGAIN1-0 bit = â01â(2 steps)ã«è¨å®ãã¦ããã¨ãALCãªã«ããªåä½ã«ã
ã£ã¦VOLå¤ã¯32Hã«å¤æ´ããã0.75dB (0.375dB x 2)å¢å ããã¾ããVOLå¤ãåºæºã¬ãã« (REFå¤)ã«éããå ´åã
VOLå¤ã®å¢å ã¯è¡ãã¾ããã
ã¾ããALCãªã«ããªå¾
æ©ä¸ã«
(ãªã«ããªå¾
æ©ã«ã¦ã³ã¿ãªã»ããã¬ãã«) ï£ Output Signal < (ãªããã¿æ¤åºã¬ãã«)
ã¨ãªã£ã¦ããå ´åãå¾
æ©ã¿ã¤ãã¯ãªã»ããããã¾ãããã®ããã
(ãªã«ããªå¾
æ©ã«ã¦ã³ã¿ãªã»ããã¬ãã«) > Output Signal
ã¨ãªã£ãæãããå¾
æ©æéã®ã«ã¦ã³ããéå§ããã¾ãã
ã¾ããALCåä½ã¯ã¤ã³ãã«ã¹æ§ã®ãã¤ãºã«ã対å¿ããALCã«ãªã£ã¦ãã¾ããã¤ã³ãã«ã¹æ§ã®ãã¤ãºãå
¥åãããå ´åã
é常ã®ãªã«ããªåä½ãããæ©ããµã¤ã¯ã«ã§ãªã«ããªåä½(ãã¡ã¼ã¹ããªã«ããªåä½)ãè¡ãã¾ããä¾ãã°ãç¬éçã«å¤§ããªé³
ãå
¥åãããå ´åããã®åä½ã«ãã大ããªé³ã«åãããå°ä¿¡å·ãæ¹åãããã¨ãã§ãã¾ãããã¡ã¼ã¹ããªã«ããªåä½ã®é
ãã¯ãRFST1-0 bits ã«ããè¨å®ãã¾ã(Table 17)ã
WTM2
0
0
0
0
1
1
1
1
WTM1
0
0
1
1
0
0
1
1
WTM0
ALCãªã«ããªå¨æ
32kHz
44.1kHz
0
128/fs
4.0ms
2.9ms
1
256/fs
8.0ms
5.8ms
0
512/fs
16.0ms
11.6ms
1
1024/fs
32.0ms
23.2ms
0
2048/fs
64.0ms
46.4ms
1
4096/fs
128.0ms
92.9ms
0
8192/fs
256.0ms
185.8ms
1
16384/fs 512.0ms
371.5ms
Table 14. ALCãªã«ããªå¾
æ©æéã®è¨å®
48kHz
2.7ms
5.3ms
10.7ms
21.3ms
42.7ms
85.3ms
170.7ms
341.3ms
(default)
RGAIN1
0
0
1
1
RGAIN0
GAIN STEP
0
1 step
0.375dB
1
2 step
0.750dB
0
3 step
1.125dB
1
4 step
1.500dB
Table 15. ALC ãªã«ããªã²ã¤ã³éã®è¨å®
(default)
MS0952-J-03
- 27 -
2013/12
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